Good question … It is physical spitting without the saliva
This is really if the thought is persisting we must try to focus … if any thought comes into our mind we should bend it towards Allah (SWT) … such that if I think of my wife then I should think Allah (SWT) gave me my wife and then use that to focus on Allah (SWT) … ultimately if such thoughts do not go away then it becomes important for me to utlise the injunction in that hadith.